Learning Forum

[Mae Kristine Labendia]

Have a pleasant day,

I would like to simulate for heat transfer of pipe about 500m length. And the simulation became slow when I will simulate it with this length. Aside from cutting pipe, can I simulate using surface and will consider various soil sorrounds from my pipe.

Thank you i advance

[Rob]

If you're pushing heat from the pipe to the soil then, yes you may want to look at the external wall options in Fluent. However, you'll then need to work out how much to alter the heat flux/temperature along the pipe. 

[C N]

Hello,

I recommend you to use follow the best practices video on how to simulate heat transfer of fluid through the pipe and also attached the user guide link on how to simulate the heat transfer in mixing elbow. This procedure will make your simulation run faster and convergence easier for the 500m length tube. If it still takes time please reduce and alter the under relaxation factor and check it will lead to faster convergence. Or you can use symmetry about y axis and give periodic condition and model half of the geometry . 

(47) Heat Transfer in a Tube with U-Bend — Simulation Example - YouTube

Chapter 5: Fluid Flow and Heat Transfer in a Mixing Elbow (ansys.com)

Thanks

Chaitanya Natraj

 

[Mae Kristine Labendia]

Hi Chaitanya Natraj,

Thank you for your help. On performing initialization, theres a warning says below screenshot. Can this affect my simulation, if so how to resolve this. Thank you.

 

 

[NickFL]

Hybrid initialization is solving an Euler solution for your problem to help orient the velocity field better than a fixed value everywhere in the flow field. There are several reasons why you could encounter the error. Look at the flow field that is produced simply by the hybrid initialization (meaning, do not iterate any further). Does it make sense? Sometimes there will be a false boundary condition or other problem that is apparent due to this warning.

If everything looks alright, then you can continue. Keep in mind, this is only an initial "guess". We will iterate towards our final solution. The final solution is independent of the initial guess (well, it should be in most cases).

[Mae Kristine Labendia]

 

 

Thank you so much for the help. I continued the simulation. But why did my contour display seems all are red. Is it reasonable? I made the same question in this thread Heat transfer result for pipe outlet (ansys.com)

Inlet temperature 573K and computed temperature around 571K. Pipe diameter is only 1.219meter and land is 10m diameter. I expect this should not became all red.

Another thing is does contour display also one of the basis of a good simulation. I came up converged model. Appreciate your help always. Thank you

 

[NickFL]

Where/what is your heat sink? If you are running a steady-state simulation, without a heat sink everything will move towards the inlet temperature.

As for you question about convergence, we cannot say. You have to take a look at the residuals and see if they are decreasing to a constant value. It is also best to monitor several other relevant quantities during the simulation to determine if the solution is converged.